EP1893705B1 - Method for producing a composite material from stones and a plastic material - Google Patents

Abstract

The invention relates to a method for stabilizing and securing banks, hillsides and slopes, and structures present at least partly in moving waters, such as supporting and construction elements, by composite materials comprising mineral particles, preferably stones, in particular crushed rock, and an epoxy resin.

Description

The invention relates to a method for producing a composite of stones with a size of 1 to 50 cm, in particular ballast, and a plastic, in particular a compact polyurethane, in particular in the attachment of banks or at least partially located in moving waters structures, as support and construction elements, can be used.

The fortification of banks, in particular embankments, is often necessary for the regulation of flowing waters. Also in new buildings and in particular in the rehabilitation of waterways and dikes must usually be a fortification of areas of the riverbank.

So far, composite bodies made of ballast and high-quality concrete were prefabricated and placed on site for such type of rehabilitation purposes. In this method, however, a renovation of damaged areas of the riverbank in place is not possible. In addition, the components usually have a very high weight. Another disadvantage of concrete is the lack of elasticity. As a result, the concrete can not cope with stresses and these composites are easily loosened.

One way of remediating damaged areas of the riverbank in situ is through the use of hardening tar formulations or liquid concrete or liquid mortars spread over the stone ballast of the embankments to be consolidated. This process can be used to stabilize the embankments for some time. However, it is above all the ecological disadvantage that over time phenolic or other environmentally harmful compounds can be released from the tar. Furthermore arise in these procedures essentially completely seamless structures. Possibly contained in the interior cavities in the bank area are filled.

The use of polyurethanes for the production of moldings with mineral ingredients and for the attachment of rock layers, especially in mining, is also known.

So describes DE 35 02 997 a process for the consolidation of geological formations in mining by polyurethane foams. Here, boreholes are introduced into the formation to be consolidated, which are filled with the mixture of liquid components for the polyurethane reaction and then sealed. The polyurethane foams and spreads through the cracks of the rock formation. By subsequent curing of the polyurethane foam, the formation is solidified. However, such a method is not applicable in the rehabilitation of embankments, in particular river bank, since foaming is not desirable there, since the penetration of water into the foam over time would cause the foam to be destroyed.

In the DE 102 41 293 A method for securing banks is described. In this case, a highly hydrophobic compact polyurethane is applied to the part of the bank that is to be attached. However, this requires a uniform surface of the corresponding bank section.

In another embodiment of this process, moldings are produced by placing rock, preferably ballast, in a mold and then applying the polyurethane system, including the liquid reaction mixture of the starting components of the polyurethane. The resulting after curing moldings can be placed on the embankment.

In both cases, however, a uniform distribution of the polyurethane on the rock is difficult to accomplish. When the system is deployed on the embankment, there may also be insufficient strengthening of the embankment, especially if the ground is uneven.

The object of the invention was to find a simple method for fixing banks, in which a high strength of the bank can be achieved and in which the fortified shore withstands high mechanical stress.

The problem could be solved by mixing in a first step in a mixing device, the liquid starting components of a plastic with stones with a size of 1 to 50 cm and in a second step, this mixture on the bank section to be fixed or at least partially in moving waters located structures, such as supporting and construction elements applied or placed in a mold where the plastic hardens.

1. a) Mischung der losen Steine mit den flüssigen Ausgangskomponenten des Kunststoffs in einem Mischer
2. b) Ausbringen dieser Mischung aus dem Mischer,
3. c) Aushärten des Kunststoffs.

The invention accordingly provides a method for producing a composite of a plastic and loose stones having a size of 1 to 50 cm, comprising the steps

1. a) Mix the loose stones with the liquid starting components of the plastic in a mixer
2. b) applying this mixture from the mixer,
3. c) curing the plastic.

The plastics may be, for example, polyurethanes, epoxy resins, unsaturated polyester resins, acrylates and methacrylates. Preference is given to using polyurethane.

The loose stones are preferably gravel, particularly preferably granite gravel. The stones have a size of 1 to 50 cm, preferably from 1 to 20 cm, particularly preferably from 2 to 15 cm, in particular from 2.5 to 6.5 cm.

As a mixer for the mixing of loose stones with the starting components of the plastic, in principle, all types of mixers can be used with which a substantially complete wetting of the stones with the liquid starting components of the plastic is possible. Mixers have proven particularly suitable which consist of an open container, for example a drum, which is preferably provided with internals. For mixing, either the drum can be rotated or the internals moved.

Such mixers are known and used for example in the construction industry for the production of concrete mixtures.

If the mixture is applied directly to the surface to be fastened, it may be advantageous to attach the mixer to a vehicle such as a tractor, a front loader or a truck. In this embodiment of the method according to the invention, the mixture can each be transported to the place where it is to be applied. After emptying the mixer, the mixture can be distributed manually, for example by raking.

In one embodiment of the method according to the invention, the mixture of the stones is carried out continuously with the liquid starting components of the plastic. For this purpose, the stones and the liquid starting components of the plastic are continuously introduced into the mixer and the wetted stones are discharged continuously. In this procedure, care must be taken that the starting materials remain in the mixer for so long that sufficient wetting of the stones can take place. Conveniently, such a mixing device can be moved along the sections to be fastened at such a speed that the stones wetted with the liquid starting components of the plastic are discharged from the mixer in such an amount as is needed for fastening. It is also possible to operate the continuous mixing device stationary and to transport the wetted stones discharged from the mixer to the desired location.

In a further embodiment of the continuous embodiment of the method according to the invention, the mixer may be a rotating drum into which there is continuous rotation Stones are introduced. This drum is equipped with nozzles that continuously distribute the starting components of the plastic on the stones. The rotation of the drum ensures a good mixing of plastic and stones. Through an opening at the end of the drum plastic / stone composites are then continuously discharged. The rotating drum can be horizontal, but also inclined at different angles to promote the discharge.

In a further embodiment of the continuous process, the stones are transported continuously on a conveyor belt which is driven through a tunnel. This has openings through which the starting materials of the plastic are continuously discharged onto the stones. At the end of the conveyor belt, the stones then fall into an open mixing drum, which discharges the composite at an adjustable conveying speed.

The thickness of the layer of the composite is preferably at least 10 cm, since at lower thicknesses the mechanical stability is often insufficient. The maximum thickness depends on the local conditions and can be up to 5 meters, for example.

In the production of moldings, the mixture of loose stones with the liquid starting components of the plastic is added after mixing in a preferably open-topped mold where the plastic cures. The resulting composite body can be applied to the shore. The shaped bodies preferably have a size of 100 + 50 × 100 + 50 × 15 + 10 cm.

The time for the mixture should be at least such that the stones are wetted as completely as possible with the liquid mixture and at most so long that the plastic is not yet cured.

It is also possible in principle to apply the loose stones in the desired thickness to the bank section to be fastened and to apply by means of a suitable device, for example a spray gun, the liquid starting components of the plastic, where they distribute and harden. Compared to the method according to the invention, however, this procedure has the disadvantage that here the distribution of the plastic is more irregular and defects, where there is no plastic, can not be excluded. Furthermore, in the presence of loosely adhering contaminants, such as sand or soil, there may be problems in adhering the stones to one another and thus in the stability of the composite.

In contrast, in the method according to the invention it is also possible to use those stones which have loosely adhering impurities on their surface. The mechanical stress during the mixing process, these impurities are removed from the surface of the stones and thus can no longer affect the adhesion of the stones together.

In a preferred embodiment of the method according to the invention can be applied to the surface of the molding sand. So that the sand adheres to the surface, the application of the sand should take place before the complete curing of the plastic.

Any sands can be used. This may be natural sand or artificial sand, such as blastfurnace slag or slag crushed sand.

In a preferred embodiment, quartz sand is used.

The grain size of the sand can vary within wide limits. Preferably, the grain size is in the usual range between 0.002-2 mm. Fine sand, that is to say those with a particle size between 0.06-0.2 mm, medium sand with a particle size between 0.2-0.6 mm and / or coarse sand with a particle size between 0.6-2.0 mm, are preferably used ,

The amount of sand should be such that the surface of the moldings is substantially covered, but there is no clogging of the pores of the molded body. Preferably, the sand is applied in an amount of 2 to 4 kg / m ^{2 of} the shaped body.

Through the sand there is an increase in the contact points between the stones. Furthermore, the sand improves the UV protection of the molding.

The rough surface caused by the sand favors the settlement of living things, such as plants and mosses on the applied moldings. This can be advantageous for example when applying the moldings in nature reserves.

The ratio of plastic to stone is chosen at least so that a sufficient strength of the composite is ensured. The exact quantities also depend, for example, on the strength of the stress on the shaped bodies at the respective bank sections.

Since the stones according to the invention are essentially connected to one another at the contact surfaces, gaps are created and the composites are permeable to water. As a result, the energy with which the water impinges on the ballast composite, adsorbed by the escape of water into cavities better and does not lead to the destruction of the molding.

Under shore can be understood in the present invention, the banks of streams, rivers or canals. Furthermore, it can be banks of lakes, reservoirs or coastal sections of seas. These can be shallow banks, embankments, dams, groynes or dikes.

Another application of the method according to the invention is the protection of structures that are at least partially in moving water, before the so-called Auskolkung. This is understood to mean a local deepening of the bottom of the flowing waters, in particular the river bottom mostly in strong water flow in Engstrecken, often on bridge piers, where due to the congestion and the subsequent stronger gradient by rotating flow, the so-called water roller, the foundations are attacked. The same effect can be found, for example, in support or bridge pillars of sea, water and / or ship bridges, port facilities, such as floating, fixed jetties, boat moorings, or water treatment plants, in wharves, boathouses, embankment walls, oil rigs, off-shore facilities, such as wind turbines, navigation marks, lighthouses, or measuring platforms, hydroelectric power plants, tunnels or stakes.

In this case, the method according to the invention can be used particularly advantageously, since other types of application of the liquid structural components of the plastic would be disadvantageous in this application. If, for example, first introduce the stones and then apply the liquid structural components of the plastic, it could come due to the movement of water to a uniform distribution of the structural components on the stones.

The geometry of the attached against the Auskolkung composites depends on the current flow conditions.

Depending on the flow conditions, the composite materials for preventing the outcrossing can be applied both directly to the structures and away from them.

By the open gap system of the composite body, which can absorb the hydrodynamic energy, thus breaking the wave, flow energy and as a result leads to significantly lower Auskolkung, damage to structures can be avoided and the carrying capacity of supporting and structural elements can be increased.

Another advantage is the easy way to make repairs to the connected.

As described, the plastics are those made from liquid starting components that cure into solid plastics. Preferably, the plastics are compact, that is they contain virtually no pores. Compared to cellular plastics, compact plastics are characterized by greater mechanical stability. Bubbles within the plastic can occur and are mostly uncritical. However, they should be minimized as much as possible.

In addition, it is preferred if the plastics are hydrophobic. This suppresses degradation of the plastics by the water.

The following can be said of the polyurethanes which are preferably used.

As structural components of the polyurethanes in the context of the present invention are understood in general compounds having free isocyanate groups and compounds having groups which are reactive with isocyanate groups. Groups which are reactive with isocyanate groups are usually hydroxyl groups or amino groups. Preference is given to hydroxyl groups, since the amino groups are very reactive and therefore the reaction mixture must be processed rapidly. The products formed by the reaction of these structural components are generally referred to below as polyurethanes.

In both process variants, it is not necessary that the stones are dry. Surprisingly, even in the presence of wet stones and even under water, it is possible to obtain good adhesion between the polyurethane and the bricks.

As polyurethanes, the customary and known compounds of this type can be used. The preparation of these materials is carried out by reacting polyisocyanates with compounds having at least two active hydrogen atoms. As polyisocyanates, it is possible in principle to use all polyisocyanates which are liquid at room temperature, mixtures and prepolymers having at least two isocyanate groups.

Preferably, aromatic polyisocyanates are used, particularly preferably isomers of toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI), in particular mixtures of MDI and polyphenylene polymethylene polyisocyanates (crude MDI). The polyisocyanates may also be modified, for example by the incorporation of isocyanurate groups and in particular by the incorporation of urethane groups. The latter compounds are prepared by reacting polyisocyanates with a deficit of compounds having at least two active hydrogen atoms and commonly referred to as NCO prepolymers. Their NCO content is usually in the range between 2 and 29 wt .-%.

As compounds having at least two isocyanate-reactive hydrogen atoms, polyfunctional alcohols, so-called polyols, or, less preferably, polyfunctional amines, are generally used.

In a preferred embodiment of the process according to the invention, those having a hydrophobic finish are used as compact polyurethanes. The hydrophobicity can be brought about in particular by addition of hydroxyl-functional oleochemical components to at least one of the starting components of the polyurethane system, preferably to the polyol component.

A number of hydroxyl functional oleochemical components are known which can be used. Examples are castor oil, hydroxyl group-modified oils such as grapeseed oil, black seed oil, pumpkin seed oil, borage seed oil, soybean oil, wheat germ oil, rapeseed oil, sunflower oil, peanut oil, apricot kernel oil, pistachio kernel oil, almond oil, olive oil, macadamia nut oil, avocado oil, sea buckthorn oil, sesame oil, hazelnut oil, evening primrose oil, wild rose oil, hemp oil , Thistle oil, walnut oil, hydroxyl-modified fatty acid esters based on myristoleic, palmitoleic, oleic, vaccenic, petroselic, gadoleic, erucic, nervonic, linoleic, linolenic, stearidonic, arachidonic, timnonic, clupanodonic, cervonic. The castor oil and its reaction products with alkylene oxides or ketone-formaldehyde resins are preferably used here. The latter compounds are sold, for example, by Bayer AG under the name Desmophen ^® 1150th

A further preferred group of oleochemical polyols can be obtained by ring opening epoxidized fatty acid esters with simultaneous reaction with alcohols and optionally following further transesterification reactions. The incorporation of hydroxyl groups in oils and fats is carried out mainly by epoxidation of the olefinic double bond contained in these products followed by the reaction of the epoxide groups formed with a monohydric or polyhydric alcohol. In this case, the epoxy ring becomes a hydroxyl group or, in the case of polyhydric alcohols, a structure with a higher number of OH groups. Since oils and fats are usually glycerol esters, parallel transesterification reactions take place in the reactions mentioned above. The compounds thus obtained preferably have a molecular weight in the range between 500 and 1500 g / mol. Such products are offered for example by the company Henkel.

In a particularly preferred embodiment of the process according to the invention is used as a compact polyurethane, which can be prepared by reacting polyisocyanates with compounds having at least two isocyanate-reactive hydrogen atoms, characterized in that the compounds containing at least two reactive hydrogen atoms at least one oleochemical polyol and at least one phenol-modified aromatic hydrocarbon resin, in particular an indene coumarone resin. These polyurethanes and their structural components have such a high hydrophobicity that they can in principle be cured even under water.

mit n von 2 bis 28 enthalten. Derartige Produkte sind handelsüblich und werden beispielsweise von der Firma Rütgers VFT AG unter dem Handelsnamen NOVARES^® angeboten.Phenol-modified aromatic hydrocarbon resins having a terminal phenol group are preferably phenol-modified indene-coumarone resins, particularly preferably technical mixtures of aromatic hydrocarbon resins, in particular those which contain as essential constituent compounds of the general formula (I)

with n from 2 to 28 included. Such products are commercially available and are offered for example by Rutgers VFT AG under the trade name NOVARES ^®.

The phenol-modified aromatic hydrocarbon resins, in particular the phenol-modified indene-coumarone resins, usually have an OH content between 0.5 and 5.0 wt .-% on.

Preferably, the fat chemical polyol and the phenol-modified aromatic hydrocarbon resin, especially the indene-coumarone resin, are used in a weight ratio of 100: 1 to 100: 50.

Together with the compounds mentioned further compounds having at least two active hydrogen atoms can be used. Due to their high hydrolysis resistance, polyether alcohols are preferred. These are prepared by customary and known processes, usually by addition of alkylene oxides to H-functional starter substances. The co-used polyether alcohols preferably have a functionality of at least 3 and a hydroxyl value of at least 400 mgKOH / g, preferably at least 600 mgKOH / g, in particular in the range of 400 to 1000 mgKOH / g. They are prepared in the usual way by reaction of at least trifunctional starting substances with alkylene oxides. As starting substances it is possible with preference to use alcohols having at least three hydroxyl groups in the molecule, for example glycerol, trimethylolpropane, pentaerythritol, sorbitol, sucrose. The alkylene oxide used is preferably propylene oxide.

The reaction mixture can be added to other conventional ingredients, such as catalysts and conventional auxiliaries and additives. In particular, desiccants, for example zeolites, should be added to the reaction mixture in order to avoid the accumulation of water in the components and thus foaming of the polyurethanes. The addition of these substances is preferably carried out to the compounds having at least two hydrogen atoms reactive with isocyanate groups. This blend is often referred to in the art as a polyol component. To improve the long-term stability of composites, it is also advantageous to add anti-microbial agents. In addition, the addition of UV stabilizers is advantageous in order to avoid embrittlement of the moldings.

The polyurethanes used can in principle be prepared without the presence of catalysts. To improve the curing catalysts can be used. As catalysts should preferably be selected those which cause the longest possible reaction time. This makes it possible for the reaction mixture to remain liquid for a long time. In principle, as described, it is possible to work without a catalyst.

The combination of the polyisocyanates with the compounds having at least two isocyanate-reactive hydrogen atoms should take place in such a ratio that a stoichiometric excess of isocyanate groups, preferably of at least 5%, in particular in the range between 5 and 60% is present.

The preferably used hydrophobic polyurethanes are characterized by a particularly good processability. Thus, these polyurethanes show a particularly good adhesion, especially on moist substrates such as wet rock, in particular granite gravel. The curing of the polyurethanes is practically compact despite the presence of water. The compact polyurethanes used show a completely compact curing even with thin layers.

Thus, the polyurethanes preferably used are excellent for fixing Uferböschungen, especially dams and dykes suitable. The bond between rock and polyurethane is very strong. Furthermore, in particular when very hydrophobic polyurethanes are used, there is practically no hydrolytic degradation of the polyurethanes and thus a very long shelf life of the embankments secured by the process according to the invention.

To carry out the process according to the invention, the polyisocyanates are preferably mixed with the compounds having at least two active hydrogen atoms and this mixture is mixed with the stones. In principle, both starting components of the polyurethane could be separately added to the stones and mixed together with them. In this case, however, it can be uneven Mixing and thus inadequate mechanical properties of the polyurethane come.

The mixing of the starting components of the polyurethane can be carried out in a known manner. In the simplest case, the components in the desired ratio in a vessel, such as a bucket, given mixed by simple stirring and then mixed in the mixing device with the stones. It is also possible to mix the starting components of the polyurethane in a mixing organ customary in polyurethane chemistry, for example a mixing head, and to bring this mixture into contact with the stones.

The invention will be explained in more detail in the following examples.

Example 1: (Production of a ballast / polyurethane composite by mechanical mixing)

In a mixing unit (type "Fliegel Duplex mixing bucket", consisting of a large mixing drum with mixing arms therein) about 1200 kg or about 0.5 m ³ gravel were registered with a mean rock size of about 2 to 10 cm. To the contents of the mixing drum were added 18 kg of a separately prepared liquid polyurethane reaction mixture, this reaction mixture being prepared from 12 kg of a polyol component called polyol component and 6 kg of a polyisocyanate called isocyanate component. The mixture of ballast and liquid polyurethane reaction mixture was thoroughly mixed in the mixing drum for about 2 to 3 minutes, so that the entire surface of the ballast stones was wetted with the polyurethane reaction mixture.

The mixing drum was placed with contents so that the contents could be spread directly to the bank area to be fixed. With Harken, this mixture of crushed stone and polyurethane reaction mixture located on its surface could be distributed in such a way that, after hardening, a uniform, approximately 30 cm thick, solid, but water-permeable composite was formed. The composite resisted the stresses caused by the water waves and thus strengthened the bank area.

Claims (18)

1. A process for the production of a composite of a plastic and loose stones having a size of from 1 to 50 cm, comprising the steps

   a) mixing of the loose stones with the liquid starting components of the plastic in a mixer,

   b) discharge of this mixture from the mixer,

   c) curing of the plastic.
2. The process according to claim 1, which is carried out batchwise.
3. The process according to claim 1, which is carried out continuously.
4. The process according to claim 1, wherein the mixture in step b) is applied to a surface to be secured or to be stabilized.
5. The process according to claim 1, wherein the mixture in step b) is introduced into a mold.
6. The process according to claim 1, wherein sand is applied to the surface of the plastic.
7. The process according to claim 1, wherein the mixture from step b) is discharged onto a surface to be secured, such as banks, hillsides or slopes and/or structures, such as supporting and construction elements, which are present at least partly in moving waters.
8. The process according to claim 1, wherein the mixture from step b) is discharged into a mold, the plastic is cured and the molding obtained in this way is applied to surfaces, such as banks, hillsides or slopes, or structures, such as supporting and construction elements, which are present at least partly in moving waters.
9. The process according to claim 1, wherein the plastic is selected from the group consisting of polyurethanes, epoxy resins, unsaturated polyester resins, acrylates and methacrylates.
10. The process according to claim 1, wherein the plastic is a polyurethane.
11. The process according to claim 10, wherein the polyurethane is hydrophobic.
12. The process according to claim 10, wherein the polyurethane is compact.
13. The process according to claim 10, wherein the compact polyurethane can be prepared by reacting

    i) polyisocyanates with

    ii) compounds having at least two hydrogen atoms reactive with isocyanate groups, and the compounds having at least two reactive hydrogen atoms comprise at least one polyol customary in fat chemistry.
14. The process according to claim 13, wherein the component ii) comprises at least one aromatic hydrocarbon resin modified with phenol.
15. The process according to claim 13, wherein the component ii) comprises at least one polyol customary in fat chemistry and at least one aromatic hydrocarbon resin modified with phenol.
16. The process according to claim 10, wherein the polyol customary in fat chemistry is selected from the group consisting of castor oil, oils modified with hydroxyl groups, such as grape-seed oil, black cumin oil, pumpkin seed oil, borage seed oil, soybean oil, wheat germ oil, rapeseed oil, sunflower oil, peanut oil, apricot kernel oil, pistachio kernel oil, almond oil, olive oil, macadamia nut oil, avocado oil, sea buckthorne oil, sesame oil, hemp oil, hazelnut oil, evening primrose oil, wild rose oil, thistle oil, walnut oil, fatty esters modified with hydroxyl groups and based on myristoleic acid, palmitoleic acid, vaccenic acid, petroselenic acid, gadoleic acid, erucic acid, nervonic acid, linoleic acid, linolenic acid, stearidonic acid, arachidonic acid, timnodonic acid, clupanodonic acid or cervonic acid, and polyols which are obtained by ring opening of epoxidized fatty esters with simultaneous reaction with alcohols.
17. The process according to claim 13, wherein the aromatic hydrocarbon resin modified with phenol is a phenol-modified indene-coumarone resin.
18. The process according to claim 13, wherein the aromatic hydrocarbon resin modified with phenol has an OH content of from 0.5 to 5.0% by weight.